"The word has been spoken - and it is referendum, so that the people can have their say whether Serbia exists in Kosovo or not," said Koštunica.

The government has not officially made the proposal public, because the document makes no mention of Serbia or its Constitution and laws, or UN Security Council Resolution 1244, but it does mention the Kosovo Constitution and laws, said Koštunica.

The former Serbian prime minister welcomed the decision of the Kosovo Serbs who established their own assembly on Monday, saying that they are the ones defending the Serbian state in Kosovo, while the government is destroying it.

The protesters shouted "treason" while passing the presidential building which was guarded by the police, and in front of the government building they called for resignations, shouting "you have betrayed Kosovo" and "Serbia has risen."

DSS supporters, who were joined by members of right-wing movements Dveri, Zavetnici and Obraz, carried the party's and the national flags, and signs which read "It is not over - the people will have their say", "'We are defending Serbia", and "Kosovo is Serbia."